沉积物中细菌叶绿素的环境指示意义

Environmental Implications of Pigments from Anoxygenic Phototrophic Bacteria in Sediments

沉积物中的光合细菌与细菌叶绿素(BChl)包含着丰富的古湖泊和古海洋信息。对光合细菌的生存环境,BChl的分布、保存、演化规律等方面进行了阐述,并探讨了湖泊和海洋沉积物中BChl的环境指示意义。BChl作为厌氧光合细菌的主要色素,不但可以指示水体中厌氧光合细菌的演变,而且能够反映化变层深度变化和水体环境特征,揭示季节性和年际尺度的气候变化。同时,根据沉积物中BChl含量可以估算古气候环境下湖泊和海洋的厌氧初级生产力。

Dense populations of photosynthetic bacteria were discovered not only in water, but also in lacustrine and littoral sediments. The pigments of phototrophic bacteria have been becoming a hot topic of scientific interest since the 1940s. Anoxygenic phototrophic bacteria live in chemocline of meromictic lakes and sea, which is the interface between oxic and anoxic mixolimnion. Depth of the H2 S chemocline, which is related to paleoclimatic and paleoenvironmental changes sensitively, is reflected by bacteriochlorophylls （BChls） in the sediment core. This paper illuminates distribution and evolution of anoxygenic photosynthetic bacteria together with their pigments. HPLC is a popular measurement for pigments. Finally, the environmental implications of fossil pigments are discussed： （1） BChls can indicate the existence of photosynthetic prokaryote; （2） As the biomarker, BChls in sediments represent the depth changes of the H2S chemocline; （3） Anoxygenic photosynthetic pigments in sediments also can be used to reconstruct the historical record of anoxygenic primary production.